Passive Radiator Myths Busted

[@DIYAudioGuy]

To learn more about ports check out this video: kzbin.info/www/bejne/o3m3eKp7fah2iNE

[@DIYAudioGuy]

@nate0 both sound fishy to me. I wouldn't have any idea how to test either.

[@DIYAudioGuy]

I wonder how many speakers get de-magnetized sitting in a pallet since they are all close together.

[@rollme1kenobi893]

Have you had the opportunity to check out any of the latest earthquake car audio. I loved them back in the early 90's, amps &subs. I was wondering if there current specs were real. 3.5 inch of x-mass for a 10 inch sub on 750 rms. 20hz for there 6x9's. Videos I've seen for the subs kind of look fake,or a science project gone wrong. Just wondering? Thanks in advance!

[@poncethegayboi]

I was going to say. Klipsch

[@HectorQuien]

I've had ported, bandpass and boxes with a passive radiator and nothing beats the tight, controlled bass response of a sealed box. Smooth as butter.

[@Carl_Jr]

I had to laugh when you were talking about port length in small enclosures. I've been caught in that conundrum. The issue is, once you make the port longer, since it occupies space inside the enclosure making it longer makes the enclosure smaller as well. It's a never-ending cycle. 🤣

[@DIYAudioGuy]

I was laughing the entire time too because I kept visualizing Michael Scott from the office saying That's what she said. But seriously, you're exactly right.

[@Carl_Jr]

@@DIYAudioGuy I've never seen that show but I've said that "quote" plenty of times. LoL You did a great job on this video! *Applause* 👏 Just one small suggestion. Put a sticker on your phone or camera or whatever you use, which points at the actual lens and reads "Look here!" to remind you to look at the actual lens. 😎 I see a lot of KZbinrs looking slightly "off point" and it's distracting. Not quite as bad as looking at someone with a stray eye, wondering if they're actually looking at you or not, but close. 🤣

[@DIYAudioGuy]

@@Carl_Jr Believe it or not, I've gotten a whole lot better at that! I think what I need to do is frame the shot and then fold the LCD screen away.

[@casemods]

Do port outside 😏

[@janinapalmer8368]

You either use a simulation program and determine all the design parameters or you make a variable volume box and stick the port outside the box ... use this for measuring the performance and plot the SPL and when you're happy with the results then you make your box ( allowing for the port volume of course)

[@25hztolife14]

Big fan of passive radiators. My floor Speakers consist of 2 active 8s and 2 passive radiators with a soft Dome. Super loud and very, very good Bass.

[@DIYAudioGuy]

Cool!

[@TEPL1]

Are they in the same enclosure by chance?

[@DaVe-iSnOtHoMe.MaN.LemmingsWeB]

Lol i went all out 1st time. Twin 15's powered an 3 high xmax 12's as passive in a extended cab f150. Lol i needed 1 more 12 passive..lol

[@djijspeakerguy4628]

It seems many people do not even know what a passive radiator is, so thanks for making this video. Some floor standing speakers, including the Polk t50, have been using passive radiators, and many people think that they are special bass speakers that have a magnet and should be wired up. They then notice their speaker is lightweight and take the “driver” out, discovering that they have a “fake speaker,” not really realizing that they were looking at a passive radiator. This has now caused more than two 1 star reviews for the t50 on Amazon.

[@DIYAudioGuy]

I made the same mistake, I literary thought companies were trying to scam me.

[@ParkerTheBasshead]

You are the best at fully explaining in a way that is easy to understand! Thanks for the great content!

[@DIYAudioGuy]

Hey man I really appreciate that!

[@KidCoyle]

@@DIYAudioGuy Parker is right. There is an enormous amount of startlingly easily-digested material in this video. Well done. Thank you.

[@DIYAudioGuy]

@@KidCoyle That seems to be my niche.

[@drrock5356]

I have 2 Skar SVR-12's in a 2.6 Cu Ft sealed enclosure in the trunk, fed with a firm 1,000 watts, and they sound great, down to about 40 hz. I recently added 2 Slaps M12V2 passive radiators, with 500g total ballast on the back of each, and now the bass goes down to 19 hz! When fed pure sine waves, at both 23 and 26 hz the entire car resonates violently, and begins to self destruct. Yet the midbass still sounds great!

[@Satch_4_Hogs]

interesting to play with PR's. In my experience, with a low tuned PR, the higher frequencies do not cause the PR to resonate nearly as much. This seems to create a situation where frequencies close to the tuning frequency the enclosure reacts more like a ported box. The further away, the enclosure acts more like a sealed box. so, in my experience, you can get the best of both worlds. Increased output at low frequencies, with tighter response at higher frequencies. The radiator does need to be properly set up with turning/mass.

[@DIYAudioGuy]

For sure

[@dylanandersen9318]

I've been super curious about a passive setup due to the space constraints in my car. Was worried that it might not sound as good as ported and wasn't sure about how to implement it. I'm definitely going to give it a shot now.

[@DIYAudioGuy]

It is a cost vs space trade off, plus the passive will roll off faster on the low end. Forget to mention that in the video. Will probably need to make another one showing that.

[@dylanandersen9318]

@@DIYAudioGuy So, you would need to tune lower to compensate?

[@DIYAudioGuy]

Probably not.

[@dtibor5903]

I use a Kicker 12 inch sub in my car. I love how little space it takes up. It is louder than my older sealed box. The pr tuning from the factory is 44-45hz, wich is not that low and I missed that powerful kick in the lungs from the sealed box. So I added weight to the pr to tune it lower a bit to about 38Hz. I used some silicone on the back of pr as weight. Like this it is just perfect.

[@dtibor5903]

@@dylanandersen9318 depends a lot on the box volume. If the box volume is larger you may end up with pr tuned already below 30 hz. Ideally for a car sub I would suggest a pr tuning to 40-35hz but that is my preference.

[@luc5731]

Earthquake had the best ones back in the day. Technique used them in home audio in the 70s n 80s.

[@ShredRMK824]

Earthquake still makes the SLAPS Series PRs. I run one with a 12 inch sub. Once tuned it increases the box output like a port.

[@Luminous.Dynamics]

​@@ShredRMK824 So my pop has a regular cab pick up truck. We're taking out 3 Kicker Comp c10s and he wanted just 2 Kicker CVR 10". The enclosure behind the seat is sealed and was made for three 10" Could I just use a single Kicker CVR 10" and get two of these passive radiators, or should it be one per sub? In which case I could just cover up the middle hole, and do a CVR 10" and a passive radiator on the other side?

[@ShredRMK824]

​@Luminous.Dynamics Use as big as a Passive radiator as the space will allow. I like to do an extended bolt out the front so I can easily change the mass without removing the PR. That allows me to tune it much quicker. Yes you can use 2 PRs it's best to have more PR cone surface area than the active drivers. The larger the PR the lower you'll be able to tune the box. Ideally if you can run 2 active 10s and a 15PR the box would have a wide dynamic range.

[@Luminous.Dynamics]

@@ShredRMK824 If I could, I would, but the box is already made and he doesnt want a different one. I was gonna just port the box with PVC pipes since theres enough airspace and just run the two CVR 10" but I think I can have him try a single 10" with one PR, although I think the box might be too big for a single 10" subwoofer. Kicker recommends 0.8-3.0 cu. ft. per sub sealed for the 10" but I dont know how factual that info is, up to 3.0 for a sealed 10" seems crazy. Thinking it should be okay though as his enclosure isnt even 2 cu ft total.

[@ShredRMK824]

I'd rather do the PR than port it. To me a small ported box sounds very muddy and you need to carefully measure for the correct port. You will need all the theile small parameters to acheive that. If you substitute one 10 PR and put a good amount of mass on it to lower the frequency you should be good. Generally I believe the 10 PRs are around 45hz with no weight on it.

[@deathstar13311]

Thanks! Great guy right here!

[@DIYAudioGuy]

Thank you very much.

[@TRONMAGNUM2099]

Good video. Do you remember the FX95's from Kraco? They had like a 6 inch woofer and a 8 inch passive radiator with a tweeter on top. Back in HS that is what people started with. My friend had them behind his front seats in his Chevy Monte Carlo. With a 140 watt Jensen amp. They were pretty loud and sounded good enough back then. So passive radiators get a thumbs up in my book.

[@DIYAudioGuy]

I don't remember that specific piece of gear but I certainly remember a Kraco! You must be an old timer like me?

[@303nitzubishi4]

I do remember those and I just saw a pair at a thrift store not too long ago! Unfortunately the foam surrounds had started deteriorating and they were asking a bit much so I passed on them

[@speedwayaudio3]

Back in the late 80's I had a Kicker Full range Box with 2 10's and a 12-inch passive radiator in the center with two tweeters on top.

[@DIYAudioGuy]

Sweet! I wish I had some pics of some of those old enclosures. I would have included them in the video.

[@speedwayaudio3]

@@DIYAudioGuy I was 23 at the time and I was the sh*t.

[@gakudzu7282]

I saw one of those once. ONCE, lol. It was damn sweet. I'm also old enough to remember when the Kicker Sidekicks came out in the early-mid '80s. 6 1/2" woofer w/8" passive and top-mount tweet. The cool kids driving old trucks could finally hear their music over their exhaust.😄

[@davidlewis8124]

Pioneer came out with some too that was TX x or something had one PR and one active driver and that was kind of an a plastic enclosure. Kicker had a Camaro box for their hatch at two horn tweeters either two 6.5" or 8" subwoofers and on the back of the box had two 10" and or 12" PRs. They were very impressive.

[@speedwayaudio3]

@@gakudzu7282 Also back in those days the Jensen Tri-ax 6x9's were king of the hill. if you did not have them, you wanted them. before I had my truck with the kicker box I had a 74 Camero with 2 EQ/Boosters and 8 Jenson's. It was very bad ass for those times.

[@SupaBuma]

Love my vintage Klipsch Chorus II's with their huge 15" passive's. Amazing bass!

[@1toonhead]

I have a passive radiator on my person extreme hi-fi unit. In one box I get 20 to 20 000 coming out on one amp. To get the passive that low I use a small dinner plate on the cone to add stiffness and weight to get the tuning. It has blown alot of people away of how it work. The 20 hert note can be heard a long way away. Been a fan of them for many years.

[@DIYAudioGuy]

Damnnnn! Hit those nasty lows!

[@swedebug2889]

I built a sub with a 12" driver and 2x10" passive radiator. With the right weights on the passive radiators it sounds very good for being DIY. :)

[@DIYAudioGuy]

Awesome!

[@NemoPropaganda]

Great vid brother!

[@DIYAudioGuy]

Thank you

[@Randy_G]

You do such a great job at explaining audio topics.

[@DIYAudioGuy]

That is the goal.

[@rosco4659]

Pioneer put passive radiators in some of there speakers, we had a pair in the common room (bar) of our barrack block. This was in 2001, I think the speakers were from the 80's and had been passed around between soldiers for years.

[@Mastermindyoung14]

You had a bar in your barracks in the early 2000s?

[@rosco4659]

@@Mastermindyoung14 Yep, we turned our common room into one.

[@Chrick]

The best thing to have 2 Passive radiators, stroke for example one one right side and one on the left side of the box is vibration cancelation of the box, specially with hevy mass on the passive radiators, for home theathre as an example, i have experimented alot with this and i can just say, they are great, with right amount of dampfaktor and headroom of the amplifier. great video by the way, it explaines all the facts.... 🙂

[@JDfromWitness]

Sometimes they can be found on large rigs as well. I have a pair of Intersonics ServoDrive ContraBass subs that each use two 15's as driven speakers and two 18 inch passive radiators.

[@DIYAudioGuy]

Very true.

[@jcweiz09]

i've never heard of a 15inch speaker with 2 18inch passive radiators. It should sound great. What I like about enclosures with passive radiator is that it sounds cleaner without the annoying port noise.

[@HifiVega]

Great video Justin! They keep getting better every week

[@BabyCharlotteschannel]

I'm not just an audiophile, but I am a technical reading geek as well, so I'm a big fan of Justin and your videos! Thank you both for helping me to learn how to get the most of every single build I do.

[@DIYAudioGuy]

I appreciate that.

[@DIYAudioGuy]

Thanks Rob!

[@HashDogg06]

Yes absolutely. I find Justin to be very engaging in his videos which makes me come back for more & his editing is great, there is never a moment i am bored.

[@njhampster]

So those Panasonic Thrusters I had back in '77 were no joke! lol Very concise explanation

[@DIYAudioGuy]

Awesome!

[@VideoGoogle2008]

Fantastic find. I’ll probably watch this a second time right after finishing it

[@DIYAudioGuy]

Thanks for watching.

[@bojow8102]

BudgetBassHead has a couple of really good box builds on his channel using passive radiators.

[@DIYAudioGuy]

Yeah, I watch his stuff.

[@trucker8084]

Kicker back in the day had a behind the seat box made for an S10 that had two six and a half inch woofers and a 10-in passive radiator and you would swear that you had two 12s behind the seat of that truck..

[@PhilLesh69]

I once had a custom made 4th order bandpass ported enclosure where we calculated low frequency wavelengths to determine the length of the internal port tube. It took one 8 inch driver and was able to handle about 400 watts.

[@DIYAudioGuy]

Cool.

[@ImpulseAudioSpeakers]

Awesome video. Perfect and easy to follow for anyone wanting to understand passive radiators.

[@DIYAudioGuy]

Thanks!

[@Harvy500]

Rel T7i subwoofers have 1 front firing 8" active driver and 1 downwards firing 10" passive driver. I've got 2. I got them a couple of months ago to upgrade my Rel T5i subwoofers. The T5i subs use a single downwards firing 8" active driver. To say the T7I'S are better is a huge understatement! Passive rads do an amazing job!!

[@ganck1147]

Yes the T7i is an awesome compact sub. I use them for music & movies & they fill up my 15ft X 18ft room effortlessly.

[@BoDiddly]

I had passive radiators in my Kenwood LS-P9000HG home speakers in my barracks when I was stationed in Okinawa (1988/89). I still have those speakers, but the foam around the radiator and the 10" active have long deteriorated. I replaced the 10" one time long ago, but I haven't found a replacement for the 430mm radiator, so I have been considering making some.

[@DIYAudioGuy]

Would this work: parts-express.sjv.io/5b2Wno

[@BoDiddly]

@@DIYAudioGuy That might actually work! The speakers were advertised as 18" passive radiator, but the actual specifications say 430mm which turns out to be 16.9 baffles.

[@westreadwell9675]

Best port explanation I’ve ever heard and I’ve been in it for nearly 20 years!

[@DIYAudioGuy]

Thanks!

[@PartsExpressOfficial]

Great Video! Thanks for sharing your knowledge!

[@DIYAudioGuy]

Glad to do it.

[@davidlewis8124]

This video is the Best one I've ever seen on PR . I have a Definitive Technology super Cube 8000 it's a beast. It punches hard and digs deep very low. And it blends perfect with ported subwoofers or sealed subwoofers. Keep teaching us more and more. Thanks for all the hard work you do. ✌️❤️

[@ponce538]

I run a pair of Polk MXT-60s, floor speakers with 2 PRs per speaker. Sound is great, and without using my subwoofer for streaming Hi-Res music. Sound is clean and deep, depending on the track. I only use my sub for movies and TV content.

[@Stan_the_Belgian]

Very clear vid, I'm also building a sub with 2 12" actives and a 18" pr, expensive but the only way to make it work without making a huuuuuge box

[@DIYAudioGuy]

That sounds pretty cool!

[@Durolith]

SMD have made nice shop speakers with 2 18'' box 3 passive in each box damn amazing setup

[@DIYAudioGuy]

Yes, I remember when he built those.

[@Skarfar90]

The "SMD Towering Towers" I too remember when he built them, and tested them out. Crazy output from a relatively small sub enclosure. By the way, he had two passive radiators per 18" driver, not three.

[@justinfoxbody]

Klipsch has been using passive radiators for years. The fort’e ii speaker has an active 12 inch driver and a passive 15 inch.

[@RWB123]

Great overview on passive radiators 👍

[@markfischer3626]

The model most appropriate for understanding woofer/enclosure mechanical performance is Newtons second law of motion applied to forced oscillation. This is an ordinary second order differential equation. Three factors affect the FR insofar as resonant frequency an Q are concerned. There's mass, springiness, and velocity related frictional loss which control the damping factor. There are two problems here as I see it. One is that you have no control over Q, the damping factor. Typically ported designs and passive designs will have a high Q. Ideal is 0.707. The other problem is that the passive is 180 degrees out of phase with the main woofer.

[@Edrop-sj3vx]

Klipsch has a powered subwoofer box that has a 10 in passive radiator with an 8 in sub and that thing was sick af never heard anything like it and it was a sealed box and it was heavy too

[@grantcain9717]

I've been waiting for you my whole life. Great vidz.

[@DIYAudioGuy]

More to come!

[@Skarfar90]

Passive radiators are awesome. If you want good bass, but don't have the space for a large ported box, PR's will be the best bet. I like how you get the good, smooth sound of a sealed box, with the higher output of a ported box. About myth #2 - You need two PR's if the specs are identical to that of the active driver (same parameters). Otherwise, use the formula

[@rawux1228]

well some plywood can be also costly to build a long port, so pr can save you from big box and complex design. And no more farts from port.

[@s.knight5991]

There's almost no information on KZbin about aperiodic vents in bass cabinets although they can be a very useful alternative for ports or passive radiators. I think it would be a good idea to make a video about that option.

[@JoshM7]

The beginning of the video reminded me of a review I've seen on Amazon of a Polk Audio Floorstanding speaker that used passive radiators and the reviewer was angry he got 2 "fake" speakers. It was the Polk T50 I believe.

[@DIYAudioGuy]

🤣

[@joeylopez8821]

Immediately thought of the same review. The guy was warning others not to buy because they are scamming people with fake speakers.

[@justinnaramor6050]

@@joeylopez8821 And then people probably were talking to the guy after the review, saying those are passive radiators. It would probably go something like this: Reviewer: "Don't buy this, the company is scamming us by using fake speakers!" People in the comments: "Lol, unfortunately you're wrong. Clearly you've never heard of a passive radiator." Or something like that. It's so silly how people immediately jump to conclusions of something being fake, instead of educating themselves on something they don't understand! It would be like saying "this person playing bagpipes is faking the performance because he takes a breath and the sound of the music is uninterrupted!" Lol! I'm not the type of person who just jumps to wrong conclusions like this... I prefer to educate myself on something I don't yet know about.

[@gtarbmx]

I have bic American hifi speakers with 2 woofers and 2 radiators of equal size. They're my favorite sounding speakers. The bass response is very linear and tight

[@TimpBizkit]

I had a set of vintage KEF with passive radiators but the bass was fairly flabby, although was still somewhat fun to listen to.

[@josephlalock8378]

i'm a fan of passive radiators. i had a pair of acculab floor speakers years back that had a 12" passive in each box. basically just a cloth covered styrofoam disk with a foam surround and no spider or even basket for that matter. very cheaply built speakers by todays standards but they sounded great! built by rtr probably about they time rtr was on the way down. i've also designed and built a small sub utilizing dual radiators that digs extemely deep for its size and i just got a package for a set of bench speakers that will each have a 7" radiator. polk used passive radiators in lots of their designs in the 80s that dug plenty deep too. one thing that i do want to mention tho, about ports. there is nothing that says you have to put a long port inside a small box. it can be on the outside. whether you want to wrap a slot port around the enclosure or do something funky with a pvc pipe. as long as the calculations are right, the tuning will be right. good video tho dude.

[@DIYAudioGuy]

You are absolutely right! The port does not have to be inside the box! I've had several viewers ask about the implications of having a port opening that was a long distance away from the subwoofer. I'm going to have to research that into a video on it.

[@josephlalock8378]

@@DIYAudioGuy cool. i'd like to see the results. that being said, i always learned that the driver and port should be as close as possible for optimum results. but then i will add to the argument of drivers on front, ports on rear. group delay, phase delay. how much can you hear, can you incorporate it optimally for your listening space...personally, i want forward firing everything and in close proximity. but i dont think a port a long distance from the driver would matter in the trunk of a car. that being said, a "stand mount" speaker who's stand is the port, exhausting at the floor in any direction, could work. that is on my to-do list one day, maybe...

[@DIYAudioGuy]

@@josephlalock8378 Right! In room/car response is a completely different beast. Plus low frequencies have long wavelengths. So many variables!

[@robertsteel3563]

My Panasonic SB-CH73 Speakers uses Passive radiators to be able to play frequencies from 22kHz all the way down to 40Hz!

[@DIYAudioGuy]

Cool.

[@TEPL1]

Quick question: I have a sealed box for two 8" CompRTs, and I'm thinking about adding two 8" passive radiators to it to add a little extra something. Two questions: 1) Since the subs are on the face of the box, could I mount the PRs on the sides? 2) Are there any cons to adding two PRs to a box with two active subs? I feel like I've only seen the 1 and 1 configurations.

[@DIYAudioGuy]

The kicker passive radiators are designed to match with their RT line of speakers. I think there's a link to them in their product description. As long as you got the air space matched up with what kicker recommends you should be just fine adding two of their passive radiators to that enclosure. They designed their passives to have more cone travel so you can do one passive per active.

[@ShredRMK824]

Usually if you don't have room in the front baffle I read somewhere to mount them in the back personally I'm not sure if it matters since they are not active so standing waves shouldn't be an issue.

[@gandalf6700]

i got a "Audio Pro Ace Bass 2" that has 4x Active units and 1 10" passive :) sounds great

[@kerzwhile]

I did Not know about the weights... What a great channel!! 😮😊

[@DIYAudioGuy]

Glad to be helpful.

[@r3alfish]

I've known about passive radiatiors since I was a kid. I can't even find a picture online of what my dad had for his Silverado but he has 2 thin boxes with a 6.5 inch speaker that acted as a mids/lows speaker and a horn Tweeter on top of the box. The passive radiator was a flat foam piece with a foam surround. The box said "Stillwater Design's" on it as did the speakers inside. The passive radiator had Kicker embossed on the front of it. They sounded great on his Kenwood cassette deck! I would still have them and be able to do something with them had my mom's ex boyfriend not left them outside. 😑

[@DIYAudioGuy]

Sounds like an original old-school box from kicker.

[@r3alfish]

@@DIYAudioGuy they could have been 8 inch drivers, I can't recall for sure. I really wish that I still had them because I tried to look them up last night and couldn't find anything like them.

[@r3alfish]

Also I was sleepy, the cassette deck was a Clarion with bright orange lights!

[@K9malinois_dog_love]

Hey, really digging the content! Quick question-do you think the 13tw5 from JL Audio, which is designed for sealed enclosures only, would get a boost from adding a passive radiator? Would love to hear what you think

[@SecretMailBand]

Absolutely great explanation! Even I (as a german - english is not my native language) understood (or not?) your very interesting videos - great!

[@DIYAudioGuy]

Thank you! 😃

[@brianraulerson5037]

Thanks, Justin! You taught me something! Between you and Nick I just might end up smart.

[@DIYAudioGuy]

Glad to help.

[@RickRogers-o8m]

We are building a subwoofer box for a live band. Our plan is to use an 18 or 21 inch woofer with six 8 inch passive radiators to try to get the deepest bass that we can. The 8" PR's are flat, not cone shaped. Does this plan sound good, or should we just go with a ported box? What do you recommend?

[@Edrop-sj3vx]

You should get six 8 in subs and get a 18 or 21 inch passive radiator the subs behind the pr

[@DIYAudioGuy]

I would go with a ported enclosure in that situation.

[@djijspeakerguy4628]

Did you know, small passive radiators are often not cone shaped, neither do they contain a spider? They are often just weighted pieces of metal with a rubber surround, as seen in most portable speakers these days. JBL, Bose, Sony, and others are using them in their Bluetooth speaker lines.

[@DIYAudioGuy]

PS Audio uses MDF for PR cones because they need a lot mass to get the desired tuning.

[@headkase11]

I have a sealed box with 6 12's 2 weeks later I saw the earthquake slap 12 passive on sale for $60 so I bought 3. I have one passive for every 2 subs and it has a fuller sound and plays a little deeper. I haven't messed with adding or subtracting weight on the passive cone. I'm waiting until I get my 5k amp to see how much they can handle. Right now my 6 12's are sharing 1200 Watts

[@DIYAudioGuy]

Unless those passives have huge X-Max you don't have enough cone area. You're probably able to get away with it since you're not hitting your subs with the full 5,000 watts.

[@TimpBizkit]

Ideally you increase the enclosure size as well.

[@headkase11]

@@TimpBizkit I added a story video with a little sound test.

[@Edward135i]

I don't understand why passive radiators aren't more popular. They are basically ports that can't chuff.

[@DIYAudioGuy]

Cost, they can be expensive.

[@raiden72]

Polk audio also did passive radiators back in the 70s (Monitor 7 vintage from 1978)

[@DIYAudioGuy]

OLD SCHOOL!

[@jub8891]

i call them passive aggressive cones

[@NackDSP]

First instinct was right. High Fidelity by definition doesn't include adding a resonance to a system. A resonator doesn't reproduce the signal, it creates a ring tone when it gets excited. Can you imagine adding a tuning fork to get more midrange? No. I gave up on resonant bass systems when I heard my first well designed sealed woofer system. If you have room for a passive radiator, spend a little more and just add a second woofer. My buddy built a system with two 10" woofers per side this fall. It is bass perfection. With proper equalization like a Linkwitz transform you can have all the clean deep bass that the radiator promises but doesn't deliver. People don't realize the transient response of these systems is bad. It takes a few cycles of the base note for the resonator to build up amplitude and you miss out on initial transient peak that a sealed system readily reproduces. Drum and plucked bass leading edges get cut in half. The transient frequency response of a ported system doesn't include any output from the port. Only a sealed system will produce the same frequency response for the transient and the steady state. This is what is called "fast bass". Ports and Radiators will always be slow muted transient bass by design with resonant overhang that was never in the music.

[@Grommet2007]

Um, sealed systems are also resonant systems. If they were not, their impedance curve would be dead flat :-)

[@NackDSP]

@@Grommet2007 Sure, sealed systems, that act as a spring, mass and damper, can be resonant systems, but they don't have to ring. If your sealed system has a low Q, like 0.5 or 0.7, it has little or no over shoot, and it doesn't ring like a bell like a passive radiator or a port must do to produce sound. A sealed woofer system can actually reproduce a bass waveform accurately because it doesn't ring. Go look at a five cycle tone burst of a woofer system with a Qb of 0.5. It doesn't resonate. It tracks the signal. Adding a resonator to a well damped woofer system is just a bad idea, and isn't high fidelity.

[@Grommet2007]

@@NackDSP Very few people build sealed systems with a Qb of 0.5, because the boxes tend to be large and the power handling at low frequencies is usually pretty crappy. In any case, put any of these bass systems in your average room and you will have to deal with very high Q resonances caused by the room's dimensions anyway.

[@robsorgdrager8477]

Now for dual iso-metric ( I think that's what it's called where two drivers face each other but are 180° faze so they act like one piston with twice the motor force ) . I also like how t lines make magic happen and folded horns are cool too.

[@DIYAudioGuy]

Iso-baric! Great idea for a video. Have you seen this one? kzbin.info/www/bejne/eae4m4qErLV7erc

[@robsorgdrager8477]

@@DIYAudioGuy thank you good sir🖖. That was actually a pretty interesting build. I personally really like the ultimax line but for half the cost and like a 1/2-2/3 the power to get that loud and low and flat....really impressive.

[@73Xtian]

The best thing about real isobaric is that you only need half the enclosure volume.

[@808bigisland]

@@73Xtian no two drivers are alike. You will equalize two/four isobaric to no end. They sound smudgy.

[@73Xtian]

@@808bigisland you're right about no two drivers being alike, but you're wrong about not getting it good and sounding 'smudgy'. Two drivers in normal configuration won't be the same either and it works perfect.

[@georgemiller8329]

Passives are less noisy or turbulent,also allow less mid frequency bleed out of port

[@DIYAudioGuy]

Right, no port noise if there is no port.

[@james10739]

Some good info I was thinking about building a Bluetooth speaker and using one in it but it was just a thought I have put zero effort into that

[@DIYAudioGuy]

You should consider a kit like this one. kzbin.info/www/bejne/maClg42MoK9gsKc

[@Anko1984]

Hello! Thanks for you explanation! You are awesome! Can i ask you a question? Is it can be enought to use two 8" PR's with one 8" Visaton BG20 in enclosure with dimensions 12x12x12 inches? I need to make a speaker, based on Visaton MB208H kit (two FR drivers BG20 + one tweeter HTH8.7), and task is to use as small enclosure as it can be, some near 12x12x30 inches! So PR's seems much better way to reduce the speaker size when port, without loose to many bass... Sorry for disturbing you, and wish you all the best!

[@DIYAudioGuy]

Yes. You are on the right track. PR's are the way to go with a small box.

[@Anko1984]

@@DIYAudioGuy thanks you very much, and wish you all the best!

[@9madness9]

Like the vid and would love to know what you make of the way kef made their KC62 Active Subwoofer

[@DIYAudioGuy]

I don't have any hands-on experience with it so I really can't say.

[@9madness9]

@@DIYAudioGuy Understand that, its an odd but cool design approach uses two 6.5 inch dual force-cancelling drivers with concentrically arranged and overlapping voice coils, driven by a single motor. They say it reduces size by a 1/3 and Frequency response from 11 Hz but not a the SPL advertised 105 dB

[@randomtube8226]

I like to use passive radiators with inverted active subs. With inverted subs I can wire directly to the subs and not have to worry about a terminal cup.

[@DIYAudioGuy]

Clever!

[@chuckmaddison2924]

Probably the one that sticks in my mind is the Celestion Ditton.

[@DIYAudioGuy]

Now that is old school right there!

[@thinkIndependent2024]

Thanks for being someone who goes with FACTS

[@DIYAudioGuy]

Facts are fun.

[@visionsofpromise]

I'll take a port over a passive radiator. That way I'm not disappointed when I look at it expecting an actual speaker

[@DIYAudioGuy]

🤣. It's funny because it's true!

[@artardFTW]

so, what's better for rock and metal music? passive radiator box or just a single woofer in a sealed enclosure

[@DIYAudioGuy]

The conventional wisdom is that you want to use a sealed enclosure for that kind of music. I disagree with conventional wisdom. Ported boxes are louder so I'm going to go with the ported box if I can. Because of the additional cost of a passive radiator it's only practical when you have limited space for the enclosure.

[@Rowuk2024]

I understand that you are trying to make a complex subject more simple, but the problem with ports AND passive radiators is that the port/radiator ONLY resonates at the tuning frequency. As that is a low frequency, more air is moving BUT not necessarily the frequency that the music is asking for. Put an accelerometer on a passive and check what the cone is actually doing. The technical description is Helmholz resonator. This is why I do not use ports or passives. My test was a port tuned to 40 Hz and the loudspeaker got fed 50 Hz. Both 40Hz and 50Hz were measurable in the listening area - hardly a goal for someone interested in sound quality. I will not go into why most people do not hear this. Only sealed boxes or open baffle are free from this effect at bass frequencies.

[@DIYAudioGuy]

Interesting. Definitely something I might need to look into.

[@memelorddavid2938]

We need shirts that say "Moon the Cone" 🤣🤣🤣

[@DIYAudioGuy]

Heck yeah! I'm thinking a big subwoofer where the speaker cone is some butt cheeks.

[@timvlogtv512]

your videos are quite informative and interesting, you earned my sub :) I'm planning to build some bookshelf speakers and im wondering if you sell any list or manual if that makes sense

[@DIYAudioGuy]

I do not, but I know someone that does. Check out Toids DIY audio. He has a ton of speaker plans available. Like these: kzbin.info/www/bejne/oojcfKd5Za2ibKs

[@killabee623]

Fist time I seen a passive radiator was in the 70's... I was like what is that woofer so flat?

[@DIYAudioGuy]

I remember thinking the same thing.

[@rgortega1285]

I have a 15 inch Sheffield Peavey 115 S Bass Amp that flutters when pushed. My concern is do I use a passive or a tube to maximize tuning of on board and frequency tuners because I'm scrap for cash and would rather solve solution of this unit which was dated back to 1994. I got this unit cheap but it was a once in a life time purchase.

[@tableseven8133]

Maybe I'm wrong but you could also use another driver not wired up as a drone as well, maybe that is where the two drone idea came from. 1 active and two not wired passive...

[@DIYAudioGuy]

If the passive still has a magnet and a voice coil then it's going to generate an electromagnetic field. It's not going to behave in a predictable way so it would not make a good passive.

[@tableseven8133]

@@DIYAudioGuy Thanks for the reply but I still wonder about that since it is not wired up the coil, it should have no resistance. Now if it was hooked up to another amp or to a light bulb then the coil's generated electricity would create a resistances, and hamper the point of a free drone.

[@livemusic8248]

I am an audiophile, i find iy fascinating, how a microphone can send sound through a cable to an amp, in turn through another cable, to a speaker that can separate, high frequencies down to low. Then one speaker company can sound realistic and another muddy, both use a cone, magnet and surround. In live music RCF, Myer, Adamson and L Acoustic and others are life like sound reproduction, and wont degrade the lesser manufactures. Then a home speaker has clarity yet only sound preproduction, while car stereos are more limited due to space. Music just gets me, how a signal is sent out and received by a receiver and one can be more sensitive example 9.3dB and another is 11.3 dB, then add stereo separation on and on. music is complex

[@DIYAudioGuy]

I think it is cool how, if you look at an audio signal on a scope, it is a big scrambled mess of different frequencies all on top of each other. Yet a speaker can play that and we recognize it as sound. Simple and complex at the same time.

[@charleshollingsworth1583]

I have a pair of klh tower home stereo speakers that has passive radiators that i paid 120 bucks each new in 1989 and in college hooked to a vintage sx 780 pioneer reciever and a vintage akai cassette deck, nad now vintage cd player then i was jamming and these things sounded great for cheap. For 20 years i never knew they had passives until one of my crack head nephews was cranking the hell out of them and blew the tweets and 1 woofer. Upon dismantling them i found 2 of the 12 inch woofers to be passive. not wanting to throw them away i looked to parts express and reloaded them with 2 fresh goldwood 12 woofers and some dayton tweets adding tweeter protection bulbs. They still sound good, they have been moved all over the country, the cabinets are getting rough as they are presswood and have been in my shop for years. i have 3 shops on my property one for wood working, one for small engine repair and one for automotive repair and all 3 have stereo systems of vintage component/pa equipment from pawn shops, ebay etc with bluetooth dongles. Reading online from a stereo review article of old states that passive radiators were used by cheap speaker companies that they did not sound good and muffelled frequenciecs now they are making big returns in speakers.

[@DIYAudioGuy]

That is awesome! Vintage gear is cool.

[@kozovokozido]

May I use one 8" active woofer and two 5" PR to keep box smallest as I can?

[@chuckymystic]

I have a box in my truck with 2 10 inch holes. It's full ported, like 3 cubic feet. I put 1 jl 10w6v3 in and blocked the other hole. It sounds amazing!! Hits pretty low freq, not sure the tuning. Question is, what would happen if I put a passive radiator in the other hole instead of it being blocked. Sounds like I'd need a huge xmax if I use the same size radiator though....

[@DIYAudioGuy]

You would need to block off the ports for it to work, and you will have a hard time finding a 10" PR with enough xmax to pair with a W6. If you go that route I would recommend cutting a bigger hole and using a 12. parts-express.sjv.io/0JN2QV

[@chuckymystic]

Thanks. Sounds good now. Next question. What happens to the frequence response if I run 2 of the w6 10s in this box? And if I push them at the same total wattage ( slash 500/1 should still give 500w at 2 or 4 ohm load ) will it be louder, the same or quieter at all frequencies?

[@garychandler4296]

Funny story: back in the '70s, I'd found 2 15" Marantz speakers atthe dump, blown I discovered. I took them and put them in 2 24" cardboard boxes and mounted an 8" car speaker on the other side of each, thinking it would magnify the bass I knew comes from the back of speakers. Hooked them up to my home stereo and man, did they sound good! I'd invented the kicker and didn't know it! Later on, I'd invent gutter helmets, vacuum sander, and several other things I probably could have retired from. Now I'm 69 and just Real Tired!

[@DIYAudioGuy]

😎

[@wilsonrawlin8547]

I'm torn between trying to create a compact ported enclosure and one with passive radiators. This is in a 2010 Tundra Crewmax behind the rear seat. Currently running two 12s in a sealed box at .85 CF for each sub.

[@DIYAudioGuy]

Tight fit!

[@wilsonrawlin8547]

@@DIYAudioGuy Lol! Yeah looks like a brady bunch family trip behind the seat. ;D

[@TimpBizkit]

You'd probably do better with one if the box volume is that small. More extension and less boomy mid bass.

[@wilsonrawlin8547]

@@TimpBizkit Good point Thanks!

[@theoriginaldonutdude4950]

If it serves as a port then why would some also include a port along with the passive radiator?

[@AndxRev]

Excellent explanation!

[@DIYAudioGuy]

Thanks

[@dash4191]

Thank you learned something new. Not a wasted day.

[@DIYAudioGuy]

Glad to hear it!

[@NemoPropaganda]

Great discussion my man.

[@DIYAudioGuy]

Thanks!

[@arcticcanoe]

Hi. I have a Small Jeep YJ without a lot of extra room. If I build a down firing sub box to go under the drivers seat. Could i put a passive radiator above it? I probably can't squeeze a very big woofer in it probably nothing bigger than a 6"or8".

[@titusm9837]

Just a crazy question - instead of using passive radiators how about normal speakers with a variable rezistor on the coil ( since you cannot tune with weights you can tune with passive rezistor). I was thinking about this since I have a few speakers that I do not use otherwise...but I could install them as passive ones.

[@DIYAudioGuy]

That's an interesting idea, I've never heard of anyone trying it. I have no idea how that would work or if it would work.

[@quangsamsungvnnvn]

i love your video . by the way . what is the best box for a passive radiator? thank you

[@DIYAudioGuy]

Depends on the driver.

[@focuspocus9774]

Jbl boombox speakers also have passive tiny subs but don't hit the low lows enough but still bassie enough

[@DIYAudioGuy]

Yes.

[@metalgearrc2166]

Hey! I have a question you may or may not want to play with. Have you ever made a box that had a larger passive radiator than the motor woofer size? My theory is if you have a large X-max on, let's say an 8" but want to get a lower hz output in a small box by adding a 10" or 12" passive radiator. Yes, I know you may have to stuff the box to help with the volume size to get it to the sweet spot. But could this be something you are interested in and see how far you are willing to go down the rabbit hole for the answer?

[@DIYAudioGuy]

You're describing the box that's in the thumbnail pic. It's a 12-in passive radiator and a 10-in subwoofer.

[@metalgearrc2166]

@@DIYAudioGuy Funny thing I missed the part where you talk about it but as soon as I see the part in the video you responded. LOL Thanks again for your work and videos!

[@jamesfalvey77]

One problem I have is having a project in mind, and like the rest of the world, I turn to KZbin for some more information. Then coming across videos like this, no offense, there's so much technical jargon that it ultimately drives me away from the project. Justin, you are very informative. Thanks for what you do

[@DIYAudioGuy]

I may need to make a video explaining the jargon.

[@carcarjinks1430]

i never understood why they don't cause phase cancellation, since the speaker is pushing the pr forward while it's moving backward

[@Rapscallion-w9o]

Is there still a volume loss when comparing a sealed box of a larger volume to a box with a passive radiator and smaller volume with the same speaker and tuned frequency?

[@DIYAudioGuy]

Any time you make the box smaller you lose output. But a passive radiator is like a port, so you get additional output. Hope that makes sense.

[@Rapscallion-w9o]

Thank you for answering my question. I was trying to figure out if adding a PR could make up for the loss of volume when decreasing box size. I don’t fully understand why box volume would decrease SPL but I suppose it makes sense if the air pressure in the box is resisting the cone movement of the speaker having less volume in the box will cause greater resistance and therefore the speaker will not be able to displace as much air/create as much pressure outside of the box.

[@H0mework]

Liked and subscribed! Great content!

[@DIYAudioGuy]

Welcome aboard!

[@JP-pc6to]

Hi. Would a front firing passive radiator be ok in a home environment. Would a cabinet with a12” active and 2 12” passives (each 1x xmas of the active) be any better or different than using only one 12” passive at 2x xmas?

[@ronwess]

Awesomeness 👌 just learned something today about passive radiator.... cool 😎 Thanks 4 this ("

[@DIYAudioGuy]

You will probably like this video as well. kzbin.info/www/bejne/o3m3eKp7fah2iNE

[@Jason_Voorhees.]

I have 2 American bass xfl 15s in a 7cuft ported box, kinda wanna seal up the port and add 4 12" passive radiators

[@DIYAudioGuy]

That's a big box.

[@beakerwsw]

Question, are passive radiators like ports where most of the sound is produced by the radiator? Like if I'm designing a box and the active driver is on one side, and the passive are on the other, will it effect output?

[@DIYAudioGuy]

Most of the sound comes from the active driver for both types and yes think if it as a port.

[@beakerwsw]

@@DIYAudioGuy I've always been told in a ported application most of the sound is made by the port.

[@DIYAudioGuy]

@@beakerwsw depending on the frequency, yes.